Water Availability Modeling in Texas

Effective management of the highly variable water resources of a river basin requires an understanding of the reliability with which various quantities of water can be supplied, under various conditions, within institutional constraints. Implementation of a water rights permit system in Texas has motivated efforts to expand capabilities for assessing water availability at any location on any stream considering the impacts of water management throughout the river basin. A surface water allocation system was implemented during the 1970's-1980's pursuant to the Water Rights Adjudication Act of 1967. The Brown-Lewis Water Management Plan enacted by the Texas Legislature in 1997 authorized development of a statewide water availability modeling system. This legislation specifies that models for six river basins are to be completed by December 1999 and models for 16 other basins must be completed by December 2001. The modeling effort is built upon the water rights permit system but is designed to support planning as well as regulatory functions.